Valves are widely used to control the flow of fluids through systems. Valve requirements vary dramatically depending upon the nature and scope of the application. In a kidney dialysis system, particularly portable kidney dialysis systems, the functional requirements for a valve include low power consumption, low heat generation, high reliability and a small, light size.
Typically, automated valves in kidney dialysis systems require energy input to maintain at least one state, namely an open state or closed state. However, the on-going need for energy input to maintain a state has substantial disadvantages. First, the system requires a higher amount of energy, thereby decreasing system mobility. Second, a system failure can cause a cut off in energy supply, thereby adversely affecting the state of a valve and causing a major secondary system failure that can hurt a kidney dialysis patient.
Valves that operate between two states (open and closed) in which energy input is required to change a state, but not to maintain a state, are known. For example, U.S. Pat. Nos. 6,836,201, 5,322,258, 6,517,045, and 7,314,208 all of which are incorporated by reference, disclose valves in which energy input is required to change a state, but not to maintain a state. However, these valve systems have not been applied, or were suggested to be applied, to the field of kidney dialysis. Moreover, they are typically not suitable for reliably maintaining the valve's closed state at the size dimensions, reliability, and force levels required by kidney dialysis systems.
In sum, valves disclosed in the medical, and more specifically kidney dialysis, fields of art are not suitable to effectively meet the aforementioned functional needs. Accordingly there is need in the prior art for an improved valve with the aforementioned attributes.